The invention relates to methods and instruments for ionizing
analyte molecules, preferably biomolecules, which are dissolved in liquids or firmly adsorbed on surfaces. Liquids are nebulized at
atmospheric pressure by electrospraying. Highly charged microdroplets, which enter the vacuum of the
mass spectrometer through the inlet capillary, strike an
impact plate when energy is fed in. The repulsive
Coulomb force of the charges, the absorption of additional
thermal energy and / or the conversion of their
kinetic energy into
thermal energy cause the microdroplets to burst and evaporate.
Analyte molecules which are located in the nebulized liquid or on the
impact plate are released in charged form and can be fed to the
mass spectrometer for analysis by the extraction and collection effect of an
ion funnel operated with RF and DC voltages.